Define modulation index. Why is it generally kept less than one ?

Explanation

### Step-by-Step Solution:

1. **Definition of Modulation Index**:
- The modulation index, often denoted by \( m \) or \( \mu \), is defined as the ratio of the amplitude of the modulating signal (the signal that carries the information) to the amplitude of the carrier wave signal (the signal that is modulated).
- Mathematically, it can be expressed as:
\[ m = \frac{A_m}{A_c} \]
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